What is CVE-2021-3942?

CVE-2021-3942 is a critical-severity vulnerability in HP Color Laserjet Cm4540 Mfp Cc419a, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2022-12-12.

How severe is CVE-2021-3942?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2021-3942 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in HP Color Laserjet Cm4540 Mfp Cc419a

CVE-2021-3942

Certain HP Print products and Digital Sending products may be vulnerable to potential remote code execution and buffer overflow with use of Link-Local Multicast Name Resolution or LLMNR.

Vulnerability class: Buffer Overflow

Published 2022-12-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.015 (73.7th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 74th percentile — 73.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.014 · newest: 0.015 · change: +0.001

Affected products

Weakness classification (CWE)

CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

Public proof-of-concept exploits

References

support.hp.com/us-en/document/ish_5948778-5949142-16/hpsbpi03780 (Vendor Advisory)

Frequently asked questions

What is CVE-2021-3942?: CVE-2021-3942 is a critical-severity vulnerability in HP Color Laserjet Cm4540 Mfp Cc419a, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2022-12-12.
How severe is CVE-2021-3942?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2021-3942 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.